Pedestrian Safety Guide and Countermeasure Selection System
A signalized intersection with a push button pedestrian activated signal.
Source: Designing for Pedestrian Safety
Automated pedestrian detection devices are able to sense when a pedestrian is waiting at a crosswalk and automatically send a signal to switch to a pedestrian WALK phase. Some automated pedestrian detection devices are also able to determine whether a pedestrian needs more time to cross the roadway and will lengthen the crossing interval to accommodate the slower pedestrian. Automated pedestrian detection devices reduce the percentage of pedestrians who cross roadways at inappropriate times, such as when the DON’T WALK signal is visible.
There are generally two types of pedestrian detection technology: microwave and infrared. A delay can be built into either of the devices so that the Walk signal is called only if the pedestrian stays within the detection zone for a certain amount of time. The delay helps to prevent pedestrians who walk by the detection zone from accidentally activating the WALK signal.
Automated pedestrian detection devices called PUFFIN (Pedestrian User-Friendly Intelligent) crossings have been in use in the United Kingdom for several years. They use an infrared detector or pressure-sensitive mat to sense pedestrians waiting for a crosswalk signal. These devices also notice if a pedestrian leaves the area and can cancel the pedestrian walk signal, if necessary. If a pedestrian takes longer than the allotted amount of time to cross the crosswalk, the PUFFIN signal is able to lengthen the WALK signal. PUFFIN crossings reduce the waiting times for pedestrians and motorists by ensuring that no signal is unnecessarily short or long.19
The cost to install a pedestrian hybrid signal system is approximately $50,000 to $120,000, depending on site conditions and what equipment is already installed. Operation costs are approximately $4,000 per year. Adding automated detectors to an existing pedestrian signal can range from $10,000 to $70,000 per crosswalk.
Authors and Acknowledgements